Custom Console PCB Advice Needed

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Skitch Patterson

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Joined
Dec 11, 2018
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2
INTRODUCTION
Hi guys, long time first time, and I've got a question I finally figured was worthy to get me to register here.  I have a console that is a one off, only built kind of thing.  It has no manual, no schematics available and nothing labeled anywhere on the PCB or elsewhere.

BACKGROUND
In about 1971/1972, the chief engineer of the Marantz Audio company, Arthur Manke, wanted to make a move into the Professional Audio market for recording.  I only know of two products that he designed and built for his company 'Manke Instruments'; a 'Wow and Flutter Meter' and a 20 channel 4 buss recording console.  The W/F Meter I've read about online, the console is in my possession.  As it turns out, Manke's hometown is about 40-50 miles away from me and I have a friend who makes his living up and down the state of California off of Craigslist, OfferUp, flea market and other second hand purchases.  Long story short, I've ended up with this console and it's actually pretty clean considering it sat for so long.  All channels pass audio, EQ pots aren't too scratchy, things work as they shouldish, I can't get anything out of the group outputs but I can get material to pass through the Foldback OUTs 1 & 2 which I think are intended as stereo or main mix outs, and the meter bridge even works for them!  Every channel has a transformer on it and I really like the sound this thing imparts.  It has a little bit of mojo just running audio through it with nothing engaged.  The EQs are really interesting to me and they don't seem to have a 'too much' point, other than the 150k, I can dime them all out more or less and it never sounds like somebody turned a knob way too much.



WHAT I WANT
The Reason I'm bringing this here is because I have very little knowledge about PCB's and channel strips overall.  I wouldn't classify myself as an idiot, I've soldered basic and obvious things like a variety of cables, patchbays, etc, simple studio things and can usually figure things out with some guidance & borrowed knowledge.  With this console being a 26 space frame, it just takes up too much room for what I would use it for.  The routing and monitor capablities are just not what I am wanting in a primary console and I already have a console that I like.  I'm not looking to cut the PCB board up and put this into a 19" rackmounted configuration.

Ultimately I want to end up with 6 or so of these guys in their own little wooden house off to the side so I can use as mic pres or channel strips to taste on a mix.

If I could get rid of everything past the main PCB/ECHO-FB-PAN switches(pictured) and end up with a line level signal somewhere that would be ideal.  If I had to keep the Fader because of volume it would be great to be able to hook a POT up to it instead of having the entire fader, just in the interest of saving room.




WHAT I THINK
I'm guessing that I'll have to find out what each of the edge connectors on the PCB board are carrying and go from there.  I'd be looking for something that is post EQ as that is kind of the point of utilizing these things.  I was figuring at the least I can go from the Foldback 2 OUT Jack on the Master section, see where that goes, then trace from there which tab on the PCB that corresponds with.  Then I would be able to set my gain level and pads, and still have an output knob for final control, if I didn't have an output control no big deal.  Unfortunately no channel has a direct out on it otherwise my situation would be far easier.  The way I've been using it currently is by running only a couple of sources through it at a time, like a drum buss for example, and using foldback 1&2 as my L&R/1&2 outputs.  Would it be possible to see what is used for the foldback outputs and just duplicate that for each strip?





WHAT I WONDER
My real problem is the power supply.  I know nothing about power, power supplies and whatever is going on in that world.  The power supply that came with it works, but is sketchy and I can't imagine I would need all it has going on for just 6 or so channels.  Is there anyway to go through a strip, find out all the different parts and capacitors and things that are on it, add together the max draw of each component and find out the max draw for each channel that way?  And in doing that, would it be wise to over-shoot whatever number the math suggests to make sure I have ample head room available?  After sorting all that info out, where could I get a power supply built to these specs?  JLM?  Would I have to get 6 individual P.S. or can I get one unit made that could power the 6?




WHAT I HAVE
I stitched together this picture(below) that is in pretty high detail, you should be able to zoom in really damn close and still see real well. If you know about this kind of thing and would benefit from some other information or more pictures of anything, please let me know.  I'm not exactly sure of everything a guy would need to get this whole thing sorted but I've got a soldering iron and solder sucker, a dual trace Oscilloscope, a Fluke 87IV Multimeter, an understanding wife and a coffee and marijuana addiction.  Any help or ideas?



Here is a link to the picture.  I uploaded it to Google Photo so I could retain as much definition as possible.
https://photos.app.goo.gl/uhX5t6M8z4FhHPGx9

Thanks,
Skitch Patterson




Edited:
Things I should add -
At the very top of the pictured PCB are the two different inputs.  A 1/4" Balanced connection and XLR Balanced connection.  The two middle pins out of the six are the grounds.
In the picture I've sat each board so that they correspond with what's on the channel strip next to it.  I mean, it's pretty obvious but I figured I'd mention it in case someone was wondering definitively.
 

gyraf

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(..formatted 2nd. paragraph, for clarity: "Ultimately I want to..")

The two 14-pin chips: What are they?

The two traces/tracks that go in-between the two rows of pins on the two IC's are most probably your +/- voltage rails.

Ground is most probably where the black wire from input transformer connects.

The lowest PCB trace (when mounted vertically), going to two precision resistors, bridged with capacitors, at the input towards top, is most probably your P48 line.

Jakob E.

 

Recording Engineer

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Joined
Jul 30, 2013
Messages
542
Location
Sacramento, CA
First, I’m curious where you are so I can invite myself to hear it! 😆 But seriously, you must be somewhat close to me. I see Arthur was born in Modesto and died in Roseville.

As for your contemplations, my first thought is why hack it up, if you can help it. What I mean is, if possible, maybe recreate a channel and the sound of it? Then you can have 6 or however many channels of it. At that point, you could do whatever you like; make more channels whenever you want, offer product or simply info to these cool dudes should they desire to recreate it themselves, keep or sell-along the console (completely gone through or as is for someone else to do), so on.

If that is too much for you to do alone, I’d get some who lives somewhat close to you get involved. I did that with someone on here who lives in Modesto. I paid for all the material and he did all the work in exchange for some end-product.

Transformers could prove to be difficult, but maybe not. I’d start there.
 

Skitch Patterson

New member
Joined
Dec 11, 2018
Messages
2
Thank you guys for the replies.

Gyraf,
The two 14 pin chips say RC4156DB RAYT7711 on them, looking like they are these:
https://www.tedss.com/RC4156DB

In regards to P48, I'm not sure if you are referring to Phantom power or not but this console unfortunately does not have said feature.

Recording Engineer, I'm located in Visalia California.  Just below Fresno and about an hour and some north of Bakersfield.  I'm not necessarily trying to hack it up,  but I have an all analog recording facility here and if I had the space to have this console readily available to run stuff through it then I would definitely keep it that way.  It has a fantastic look to it, I mean it's one of those things that's almost worth having even if it didn't work just because it looks so GD cool.  BUT, the functionality of it doesn't give me the flexibility I need in regards to routing and just some features that I do like to have in a console and it is a fair size, I just don't have the room to have the entire thing in the control room on the ready, and it's just not got the routing to be my main guy.

I actually think what you are saying here is what I'm intending to do, but if the volume fader and buss assignment switches and all that aren't doing anything but taking up real estate, I'm fine with getting them out of there.  Being that it was made in the very early 70's and the way it seems to be laid out for use suggests to me that it was a tracking console and not necessarily a mixing desk.  It has 6 XLR inputs and 20 Line inputs, 4 group outs and two foldback outputs and that's it for any connections.

Anyway, I'm not really wanting to hack it up, I'm looking to use 6 channels independently of the rest of the console/master section and add direct outputs to them so I can send straight into the tape deck from there, or where ever I wish to go with the signal.  They're all modular channels so it really doesn't seem too hard, I just don't really understand IC's, PCBs and all the stuff that I'm looking at in here, the power issue being my main question mark.  I guess this is the point where I start learning this stuff. 

I've already made good progress tonight towards getting what I want.  I've figured out I can come out of pin 6(from the bottom) and that gives me the FoldBack 2 return POT which I can select if I want pre or post EQ.  So now i'm figuring I need to look at the other end of the console and see how the Foldback outputs are done, if they are balanced or how it's being fed out, and if I can replicate that for each channel that will give me the direct out per-channel that I am looking for.  If I can get a Direct Out on each channel and figure out the power, I'm in business.  That's what I'm after.  Then, if I'm happy with my six, and it sounds cool and some people are interested I can sell the remaining channel strips or do whatever really. 

I've thought that if I learn enough in the process I may decide to make a little 8 channel mixer or something maybe.  I'd love to get someone around my area involved and helping out on this if for no other reason than I find that the best way for me to learn, but there isn't anyone that I'm aware of around here that does this kind of thing, or would be interested in doing it.  Mostly plug-in and Pro-Tool techs around this area that if I were to mention it they would say, "Oh why waste all that time?! Get a plugin!" as they gaze into Fakebook on their phones.
 

Bo Deadly

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Dec 22, 2015
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I've read everything you said and I'm glad you posted this here because this is exactly the sort of thing I love to look at. Please post more pictures. Wide angle shots. Dimensions.

What are the dimensions of each channel? Looks like say 32" L x 1.4" W x 20 ch = 44.8" total width  / 2 makes two sets of 10 ch ~22.4" wide (mmm, pretty close to 19"). Now make a wood box out of 3/8. If you want to be clever you could add flight case hardware so that they bolt together face-to-face. If you do two slanted racks they still fit together face-to-face. The details can be drafted using Sketchup in no time.

Once you have them mounted and protected you can decide further what to do precisely.

I would definitely try to get it working. But I would be careful about putting too much front-loaded work into it. I would do the bare minimum.

The power supply is no problem. Just get two Mean Well LPC-35-1400 SMPS from Mouser for $13.97 each (or maybe APC-25-250 or one PCB-100B). Then also get a dual +- 15V LM317 / LM337 based power supply from Eby or countless other places that look like this:

dualsup.png


But I would get one where the metal face of the two regulator chips is facing out so that they can be mounted face down (probably soldered from beneath) onto a larger heat sink. The "heat sink" could just be some scrap metal but the face has to be very smooth (mounting the regulators requires care).

Then you run mains AC into the SMPS and then wire the - out of one to the + of the other. That intersection makes ground and relative to that you have +24V and -24V. Then, after modifying the regulator board quite a bit (you might want to buy one that's just a kit) you feed the +-24 in and adjust those trimmers to get +-15V out. That's it!
 

iampoor1

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Joined
May 11, 2013
Messages
692
Location
California
I've sent you a PM with my phone number. I actually have 20 of these strips in my shop, 10 are being converted into a sidecar, the other 10 will be racked up in pairs of 2...
I would be glad to do this for you if you don't want to go through the whole process.

I am in modesto, but the owner of the console that I pulled apart is from visalia, you might know him!
 

Recording Engineer

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Jul 30, 2013
Messages
542
Location
Sacramento, CA
I know exactly what you mean about space for a side-car console. I hauled a console to 3 different studios of mine over 20 years strictly for the preamps in it. When I got an SSL 6048, I no longer could fit it in the control room, so that was the time to copy the preamps in a nice rack and let the console go. I did have to pull the preamp  input transformers from the console though as they are a mystery. I do wish to get another channel-strip to have a transformer to sacrifice so I can have a company recreate it at some point.

By the way, iampoor1 is who helped me with my project.
 

MidnightArrakis

Well-known member
Joined
Sep 25, 2015
Messages
68
INTRODUCTION
Hi guys, long time first time, and I've got a question I finally figured was worthy to get me to register here. I have a console that is a one off, only built kind of thing. It has no manual, no schematics available and nothing labeled anywhere on the PCB or elsewhere.

BACKGROUND
In about 1971/1972, the chief engineer of the Marantz Audio company, Arthur Manke, wanted to make a move into the Professional Audio market for recording. I only know of two products that he designed and built for his company 'Manke Instruments'; a 'Wow and Flutter Meter' and a 20 channel 4 buss recording console. The W/F Meter I've read about online, the console is in my possession. As it turns out, Manke's hometown is about 40-50 miles away from me and I have a friend who makes his living up and down the state of California off of Craigslist, OfferUp, flea market and other second hand purchases. Long story short, I've ended up with this console and it's actually pretty clean considering it sat for so long. All channels pass audio, EQ pots aren't too scratchy, things work as they shouldish, I can't get anything out of the group outputs but I can get material to pass through the Foldback OUTs 1 & 2 which I think are intended as stereo or main mix outs, and the meter bridge even works for them! Every channel has a transformer on it and I really like the sound this thing imparts. It has a little bit of mojo just running audio through it with nothing engaged. The EQs are really interesting to me and they don't seem to have a 'too much' point, other than the 150k, I can dime them all out more or less and it never sounds like somebody turned a knob way too much.



WHAT I WANT
The Reason I'm bringing this here is because I have very little knowledge about PCB's and channel strips overall. I wouldn't classify myself as an idiot, I've soldered basic and obvious things like a variety of cables, patchbays, etc, simple studio things and can usually figure things out with some guidance & borrowed knowledge. With this console being a 26 space frame, it just takes up too much room for what I would use it for. The routing and monitor capablities are just not what I am wanting in a primary console and I already have a console that I like. I'm not looking to cut the PCB board up and put this into a 19" rackmounted configuration.

Ultimately I want to end up with 6 or so of these guys in their own little wooden house off to the side so I can use as mic pres or channel strips to taste on a mix.

If I could get rid of everything past the main PCB/ECHO-FB-PAN switches(pictured) and end up with a line level signal somewhere that would be ideal. If I had to keep the Fader because of volume it would be great to be able to hook a POT up to it instead of having the entire fader, just in the interest of saving room.




WHAT I THINK
I'm guessing that I'll have to find out what each of the edge connectors on the PCB board are carrying and go from there. I'd be looking for something that is post EQ as that is kind of the point of utilizing these things. I was figuring at the least I can go from the Foldback 2 OUT Jack on the Master section, see where that goes, then trace from there which tab on the PCB that corresponds with. Then I would be able to set my gain level and pads, and still have an output knob for final control, if I didn't have an output control no big deal. Unfortunately no channel has a direct out on it otherwise my situation would be far easier. The way I've been using it currently is by running only a couple of sources through it at a time, like a drum buss for example, and using foldback 1&2 as my L&R/1&2 outputs. Would it be possible to see what is used for the foldback outputs and just duplicate that for each strip?





WHAT I WONDER
My real problem is the power supply. I know nothing about power, power supplies and whatever is going on in that world. The power supply that came with it works, but is sketchy and I can't imagine I would need all it has going on for just 6 or so channels. Is there anyway to go through a strip, find out all the different parts and capacitors and things that are on it, add together the max draw of each component and find out the max draw for each channel that way? And in doing that, would it be wise to over-shoot whatever number the math suggests to make sure I have ample head room available? After sorting all that info out, where could I get a power supply built to these specs? JLM? Would I have to get 6 individual P.S. or can I get one unit made that could power the 6?




WHAT I HAVE
I stitched together this picture(below) that is in pretty high detail, you should be able to zoom in really damn close and still see real well. If you know about this kind of thing and would benefit from some other information or more pictures of anything, please let me know. I'm not exactly sure of everything a guy would need to get this whole thing sorted but I've got a soldering iron and solder sucker, a dual trace Oscilloscope, a Fluke 87IV Multimeter, an understanding wife and a coffee and marijuana addiction. Any help or ideas?



Here is a link to the picture. I uploaded it to Google Photo so I could retain as much definition as possible.

Thanks,
Skitch Patterson




Edited:
Things I should add -
At the very top of the pictured PCB are the two different inputs. A 1/4" Balanced connection and XLR Balanced connection. The two middle pins out of the six are the grounds.
In the picture I've sat each board so that they correspond with what's on the channel strip next to it. I mean, it's pretty obvious but I figured I'd mention it in case someone was wondering definitively.
Your thread just showed up in one of my discussion forums and even though I'm 3-1/2 years late to this party, I thought I would still add-in my 2-cents worth to this discussion, should you still be working on this project. Ready???

Since you are/were wanting to make some kind of - separate - item out of the channel strip, I could "Reverse-Engineer" the PCB for you as either an entire PCB "as is", or as multiple smaller PCB's that connect together in some manner. Additionally, I could also design for you either a "regular" channel-strip metal faceplate or, install the PCBs into a 1U rack-chassis enclosure. Whatever type of mechanical or PCB design that you wish to have, I could custom design whatever it is you need for you. That's what I do!!!

Also, please keep in mind.....that the RC4156 IC chips were nearly the ruin of many "Pro-Audio" companies back in the 1970s, with CROWN International being one of the largest sufferers during that time!!! CROWN nearly went bankrupt due to the problems that their use of the RC4156 caused them!!! There are many drop-in replacements of modern IC's that you could use instead. RUNAWAY AS FAST AS YOU CAN FROM THE RC4156 IC CHIP!!!

Also, instead of - drilling - out any new holes for your XLR connectors, you will be much better off using a GREENLEE punch instead. They work lots better.
/
 

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